Article made of conglomerate material and method for manufacturing such article

Abstract

Article made of conglomerate material in the form of a slab including an aggregate which includes granules of expanded material having a selected particle size range and defining between them inter-granular cavities containing only air and no filling material. The aggregate also includes a binder present in a controlled minimum quantity sufficient for lining the granules of expanded material. The article also includes a lining layer integral with the aggregate. Also, a method for the production of an article made of conglomerate material.

The invention claimed is: 
     
         1 . A method for production of an article made of conglomerate material in the form of a slab and comprising an aggregate, the method comprising the following steps:
 preparation of an initial mix containing granules of expanded material and a binder, the granules of expanded material forming inter-granular cavities there between;   deposition of said mix on a temporary support or in a mould;   compaction of said mix;   hardening of said binder and said mix so as to form the aggregate and obtain the article in slab form;   wherein said binder is present in a minimum controlled volumetric quantity sufficient for lining the granules, the inter-granular cavities formed between said granules containing only air and being without filling material; and   wherein the volumetric quantity of said binder is between 8% and 10% by volume of a total volume of the article;   characterized in that the method comprises at least one step of applying a lining layer on at least one surface of said aggregate, said lining layer being integral with said aggregate after said at least one application step.   
     
     
         2 . The method according to  claim 1 , characterized in that said granules of expanded material are granules of expanded glass and/or granules of expanded ceramic/clay. 
     
     
         3 . The method according to  claim 2 , characterized in that said binder comprises an aqueous dispersion of sodium silicate or an aqueous dispersion of potassium silicate or an aqueous dispersion of colloidal silica, or mixtures thereof, the aqueous dispersion containing water. 
     
     
         4 . The method according to  claim 3 , characterized in that said hardening step is performed by means of evaporation of the water, optionally accelerated by means of heating and consequent drying of the article. 
     
     
         5 . The method according to  claim 3 , characterized in that said binder hardening step is performed by blowing carbon dioxide into the inter-granular cavities of the expanded material, with subsequent drying and elimination of the water. 
     
     
         6 . The method according to  claim 2 , characterized in that said lining layer is a glass-based and/or ceramic-based and/or clay-based enamel, which is applied after a step for drying the article. 
     
     
         7 . The method according to  claim 4 , characterized in that, downstream of said drying and hardening step, there is a step of heating and firing the article to a predetermined temperature suitable for consolidating the article with the lining layer. 
     
     
         8 . The method according to  claim 7 , characterized in that said predetermined heating and firing step is less than about 700° C.-750° C. 
     
     
         9 . The method according to  claim 7 , characterized in that firing of the lining layer and firing of the aggregate of the article are performed simultaneously in a single heating step.